This invention relates to passive transmitters, and more particularly to a passive transmitter incorporating a parametric device.
Parametric devices are used in frequency multipliers and dividers, and generally require a local source of power providing an input to a parametric device at a first or pump frequency. It is important that a passive transmitter include a limited number of stages since very limited power, namely power derived from an external source, is available for operation. It is desirable to provide a passive transmitter which does not include a local amplifier and yet which can produce a usable output signal. It is also desirable to provide modulation means in a passive transmitter so the passive transmitter can produce output signals bearing information. Further, parametric amplifiers often require idler circuits which are necessary to provide a signal circulation path for frequencies such as the frequency corresponding to the difference between the pump frequency and the output frequency. If an idler circuit can be eliminated, simplicity of a passive transmitter is enhanced.